Reduction of atherosclerotic nanoplaque formation and size by Ginkgo biloba (EGb 761) in cardiovascular high-risk patients

New insights into the therapeutic options to lower lipoprotein(a)

BACKGROUND

Elevated levels of lipoprotein(a) [Lp(a)] represent a risk factor for cardiovascular disease including aortic valve stenosis, myocardial infarction and stroke. While the patho-physiological mechanisms linking Lp(a) with atherosclerosis are not fully understood, from genetic studies that lower Lp(a) levels protect from CVD independently of other risk factors including lipids and lipoproteins. Hereby, Lp(a) has been considered an appealing pharmacological target.

RESULTS

However, approved lipid lowering therapies such as statins, ezetimibe or PCSK9 inhibitors have a neutral to modest effect on Lp(a) levels, thus prompting the development of new strategies selectively targeting Lp(a). These include antisense oligonucleotides and small interfering RNAs (siRNAs) directed towards apolipoprotein(a) [Apo(a)], which are in advanced phase of clinical development. More recently, additional approaches including inhibitors of Apo(a) and gene editing approaches via CRISPR-Cas9 technology entered early clinical development.

CONCLUSION

If the results from the cardiovascular outcome trials, designed to demonstrate whether the reduction of Lp(a) of more than 80% as observed with pelacarsen, olpasiran or lepodisiran translates into the decrease of cardiovascular mortality and major adverse cardiovascular events, will be positive, lowering Lp(a) will become a new additional target in the management of patients with elevated cardiovascular risk.

The molecular mechanisms of ginkgo (Ginkgo biloba) activity in signaling pathways: A comprehensive review

BACKGROUND

One of the most unique plants that have ever grown on the planet is Ginkgo biloba L., a member of the Ginkgoaceae family with no close living relatives. The existence of several differently structured components of G. biloba has increased the chemical variety of herbal therapy. Numerous studies that investigated the biochemical characteristics of G. biloba suggest this plant as a potential treatment for many illnesses.

PURPOSE

Review the molecular mechanisms involved in the signaling pathways of G. biloba activity in varied circumstances and its potential as a novel treatment for various illnesses.

METHODS

Studies focusing on the molecular processes and signaling pathways of compounds and extracts of G. biloba were found and summarized using the proper keywords and operators from Google Scholar, PubMed, Web of Science, and Scopus without time restrictions.

RESULTS

G. biloba exerts its effects through its anti-inflammatory, anti-apoptotic, anti-cancer, neuroprotective, cardioprotective, hepatoprotective, antiviral, antibacterial, pulmoprotective, renoprotective, anti-osteoporosis, anti-melanogenic, retinoprotective, otoprotective, adipogenic, and anti-adipogenic properties. The most important mechanisms involved in these actions are altering the elevation of ROS formation, inhibiting NADPH oxidases activation, altering the expression of antioxidant enzymes, downregulating MAPKs (p38 MAPK and ERK, and JNK) and AP-1, increasing cAMP, inactivating Stat5, activating the AMPK signaling pathway, affecting Stat3/JAK2, NF-κB, Nrf-2, mTOR, HGF/c-Met, Wnt/β-catenin and BMP signaling pathways, and changing the mitochondrial transmembrane potential, the Bax/Bcl-2 ratio, the release of Cyc from mitochondria to cytosol, the protein cleavage of caspases 3, 7, 8, 9, and 12, poly (ADP-ribose) polymerase, and MMPs levels.

CONCLUSIONS

G. biloba and its components have gained attention in recent years for their therapeutic benefits, such as their anti-inflammatory, antioxidant, anti-apoptotic, and apoptotic effects. By understanding their molecular mechanisms and signaling pathways, potential novel medicines might be developed in response to the rising public desire for new therapies.

Ginkgo biloba attenuated detrimental inflammatory and oxidative events due to Trypanosoma brucei rhodesiense in mice treated with melarsoprol

BACKGROUND

The severe late stage Human African Trypanosomiasis (HAT) caused by Trypanosoma brucei rhodesiense (T.b.r) is characterized by damage to the blood brain barrier, severe brain inflammation, oxidative stress and organ damage. Melarsoprol (MelB) is currently the only treatment available for this disease. MelB use is limited by its lethal neurotoxicity due to post-treatment reactive encephalopathy. This study sought to assess the potential of Ginkgo biloba (GB), a potent anti-inflammatory and antioxidant, to protect the integrity of the blood brain barrier and ameliorate detrimental inflammatory and oxidative events due to T.b.r in mice treated with MelB.

METHODOLOGY

Group one constituted the control; group two was infected with T.b.r; group three was infected with T.b.r and treated with 2.2 mg/kg melarsoprol for 10 days; group four was infected with T.b.r and administered with GB 80 mg/kg for 30 days; group five was given GB 80mg/kg for two weeks before infection with T.b.r, and continued thereafter and group six was infected with T.b.r, administered with GB and treated with MelB.

RESULTS

Co-administration of MelB and GB improved the survival rate of infected mice. When administered separately, MelB and GB protected the integrity of the blood brain barrier and improved neurological function in infected mice. Furthermore, the administration of MelB and GB prevented T.b.r-induced microcytic hypochromic anaemia and thrombocytopenia, as well as T.b.r-driven downregulation of total WBCs. Glutathione analysis showed that co-administration of MelB and GB prevented T.b.r-induced oxidative stress in the brain, spleen, heart and lungs. Notably, GB averted peroxidation and oxidant damage by ameliorating T.b.r and MelB-driven elevation of malondialdehyde (MDA) in the brain, kidney and liver. In fact, the co-administered group for the liver, registered the lowest MDA levels for infected mice. T.b.r-driven elevation of serum TNF-α, IFN-γ, uric acid and urea was abrogated by MelB and GB. Co-administration of MelB and GB was most effective in stabilizing TNFα levels. GB attenuated T.b.r and MelB-driven up-regulation of nitrite.

CONCLUSION

Utilization of GB as an adjuvant therapy may ameliorate detrimental effects caused by T.b.r infection and MelB toxicity during late stage HAT.

Ginkgo biloba extract alleviates fatty liver hemorrhagic syndrome in laying hens via reshaping gut microbiota

BACKGROUND

Ginkgo biloba extract (GBE) is evidenced to be effective in the prevention and alleviation of metabolic disorders, including obesity, diabetes and fatty liver disease. However, the role of GBE in alleviating fatty liver hemorrhagic syndrome (FLHS) in laying hens and the underlying mechanisms remain to be elucidated. Here, we investigated the effects of GBE on relieving FLHS with an emphasis on the modulatory role of GBE in chicken gut microbiota.

RESULTS

The results showed that GBE treatment ameliorated biochemical blood indicators in high-fat diet (HFD)-induced FLHS laying hen model by decreasing the levels of TG, TC, ALT and ALP. The lipid accumulation and pathological score of liver were also relieved after GBE treatment. Moreover, GBE treatment enhanced the antioxidant activity of liver and serum by increasing GSH, SOD, T-AOC, GSH-PX and reducing MDA, and downregulated the expression of genes related to lipid synthesis (FAS, LXRα, GPAT1, PPARγ and ChREBP1) and inflammatory cytokines (TNF-α, IL-6, TLR4 and NF-κB) in the liver. Microbial profiling analysis revealed that GBE treatment reshaped the HFD-perturbed gut microbiota, particularly elevated the abundance of Megasphaera in the cecum. Meanwhile, targeted metabolomic analysis of SCFAs revealed that GBE treatment significantly promoted the production of total SCFAs, acetate and propionate, which were positively correlated with the GBE-enriched gut microbiota. Finally, we confirmed that the GBE-altered gut microbiota was sufficient to alleviate FLHS by fecal microbiota transplantation (FMT).

CONCLUSIONS

We provided evidence that GBE alleviated FLHS in HFD-induced laying hens through reshaping the composition of gut microbiota. Our findings shed light on mechanism underlying the anti-FLHS efficacy of GBE and lay foundations for future use of GBE as additive to prevent and control FLHS in laying hen industry.

Molecular Characterization and Genetic Diversity of Ginkgo (Ginkgo biloba L.) Based on Insertions and Deletions (InDel) Markers

As a "living fossil", ginkgo (Ginkgo biloba L.) has significant ornamental, medicinal, and timber value. However, the breeding improvement of ginkgo was limited by the lack of enough excellent germplasms and suitable molecular markers. Here, we characterized numerous polymorphic insertion/deletion (InDel) markers using RAD-seq in 12 different ginkgo cultivars. The total of 279,534 InDels identified were unequally distributed across 12 chromosomes in the ginkgo genome. Of these, 52.56% (146,919) and 47.44% (132,615) were attributed to insertions and deletions, respectively. After random selection and validation, 26 pairs of polymorphic primers were used for molecular diversity analysis in 87 ginkgo cultivars and clones. The average values of observed heterozygosity and polymorphism information were 0.625 and 0.517, respectively. The results of population structure analyses were similar to those of neighbor-joining and principal component analyses, which divided all germplasms into two distinct groups. Moreover, 11 ginkgo core collections accounted for approximately 12.64% of the total ginkgo germplasms obtained, representing well the allelic diversity of all original germplasms. Therefore, these InDels can be used for germplasm management and genetic diversity analyses in ginkgo and the core collections will be used effectively for ginkgo genetic improvement.

Novel mechanisms for the synthesis of important secondary metabolites in Ginkgo biloba seed revealed by multi-omics data

Although the detailed biosynthetic mechanism is still unclear, the unique secondary metabolites of Ginkgo biloba, including ginkgolic acids (GAs) and terpene trilactones, have attracted increasing attention for their potent medicinal, physiological and biochemical properties. In particular, GAs have shown great potential in the fields of antibacterial and insecticidal activities, making it urgent to elucidate their biosynthetic mechanism. In this study, we systematically revealed the landscape of metabolic-transcriptional regulation across continuous growth stages of G. biloba seeds (GBS) based on multi-omics mining and experimental verification, and successfully identified all major types of GAs and terpene trilactones along with more than a thousand kinds of other metabolites. The phenological changes and the essential gene families associated with these unique metabolites were analyzed in detail, and several potential regulatory factors were successfully identified based on co-expression association analysis. In addition, we unexpectedly found the close relationship between large introns and the biosynthesis of these secondary metabolites. These genes with large introns related to the synthesis of secondary metabolites showed higher gene expression and expression stability in different tissues or growth stages. Our results may provide a new perspective for the study of the regulatory mechanism of these unique secondary metabolites in GBS.

A randomized, open-label clinical trial in mild cognitive impairment with EGb 761 examining blood markers of inflammation and oxidative stress

Although beta-amyloid (Aβ) and phosphorylated tau remain the preferred targets for disease-modifying treatments (DMT) against Alzheimer's disease (AD), part of the pathophysiological mechanisms of cognitive impairment are related to neuroinflammation and oxidative stress. In mild cognitive impairment (MCI), a prodromal stage of AD and other neurodegenerative conditions, the joint appearance of inflammation, oxidative stress, and metabolic alterations are the common pathways of neurotoxicity and neurodegeneration. The standardized extract of Ginkgo biloba EGb 761 interferes with the pathogenic mechanisms involved in both the development of cognitive impairment due to AD and that of vascular origin. The primary objective of this study is to compare changes in the levels of blood markers of inflammation and oxidative stress after treatment with EGb 761 in a cohort of 100 patients with MCI. In addition, we aim to assess changes in these blood markers during an additional 12-month extension phase in which patients in the control group will also receive EGb 761 and patients in the active group will extend their treatment duration. Secondary objectives include comparing changes in neuropsychiatric and cognitive test scores between the baseline (v0) and 12-month visits (v2). This study is a Phase IV, single-center, randomized, open-label, parallel-group clinical trial consisting of the 12-month follow-up of a cohort of participants with MCI [Global Deterioration Scale (GDS) = 3] and an extension with an additional 12-month follow-up. During the first 12 months, participants will be randomized into two arms: in one arm, patients will receive 1 daily tablet of EGb 761 240 mg orally (study group, n = 50), while in the other arm, patients will not receive EGb 761 and will undergo the same assessments as the treated group (control group, n = 50). After the first 12 months of the study, patients in the EGb 761-treated group will continue treatment, and patients in the control group will be offered one EGb 761 240 mg tablet per day orally. All participants will be monitored for an additional 12 months. A battery of blood markers of inflammation and oxidative stress will be quantified at v0, v1, v2, v3, and v4. The Olink Proteomics panel of inflammation markers ( https://www.olink.com/products/inflammation/ ) will be used to evaluate 92 proteins associated with inflammatory diseases and related biological processes. The second panel measures 92 proteins involved in neurological processes. At v0, v2, and v4, neuropsychological and neurological evaluations will be conducted in addition to vital signs and anthropometric studies using a body composition monitor with bioimpedance technology (Tanita). Sixty percent of the 100 MCI patients recruited were women. The mean age was 73.1 years, and the mean time between symptom onset and MCI diagnosis was 2.9 years. The mean Mini-Mental State Examination (MMSE) score was 26.7. Depressive and anxiety disorders, as well as vascular risk factors, were the most frequent comorbidities among the cohort. The study is still ongoing, and results for the first year of treatment (v0, v1, v2) are expected by 2023. Individuals with MCI have an elevated risk of developing dementia. EGb 761 is used worldwide for the symptomatic treatment of cognitive disorders due to its neuroprotective effects. In experimental models and clinical observational studies, EGb 761 has shown strong antioxidant and anti-inflammatory activity. As a result, this study has been proposed to evaluate the antioxidant and anti-inflammatory effects on plasma markers and their potential clinical correlation with the progression of cognitive decline in patients with MCI.Trial registration: Registro Español de estudios clínicos (REec) number 2020-003776-41, ClinicalTrials.gov Identifier: NCT05594355.

Coronary bioresorbable stents: Non-invasive quantitative evaluation of intra- and juxta-stent plaque composition-A computed tomography longitudinal study

PURPOSE

Coronary bioresorbable stents (BRS) do not produce blooming artifacts on computed tomography (CT), in contrast to metallic stents, as they are made of a bioresorbable polymer and are radiolucent. They allow to evaluate the coronary plaque beneath. The low-attenuation plaque (LAP) suggests plaque vulnerability and is CT assessable. The aim of our study was to show the possibility of a non-invasive CT evaluation of the volume and the LAP composition of the intra- and juxta-stent plaque.

METHODOLOGY

In our prospective longitudinal study, we recruited 27 consecutive patients (35 BRS stents total; mean age 60 +/- 9 years) with bioresorbable stents for a 256-slice ECG-synchronized CT evaluation at 1- and 12-months post stent implantation. Total plaque volume (mm3), absolute and relative (%) LAP volume per block in the pre- intra- and post-stent zones were analyzed; comparison 1- and 12-months post-implantation of BRS. Changes in the previously mentioned variables were assessed by the mixed effects models with and without spline, which also accounted for the correlation between repeated measurements.

RESULTS

Our block or spline model analysis has shown no significant difference in plaque or absolute LAP volumes in pre- intra- and post-stent zones between 1 and 12 months. Interestingly, % LAP volume increases near-significantly in the distal block of the intrastent at 12-mo follow-up (from 23.38 ± 1.80% to 26.90 ± 2.22% (increase of 15%), p = 0.052).

CONCLUSION

Our study demonstrates the feasibility of the repeated non-invasive quantitative analysis of the intrastent coronary plaque and of the in-stent lumen by CT scan.

Ginkgo biloba extract ameliorates atherosclerosis via rebalancing gut flora and microbial metabolism

The Ginkgo biloba leave extract (GbE) is widely applied in the prevention and treatment of atherosclerotic cardiovascular diseases in clinical practice. However, its mechanism of actions has not been totally elucidated. In this study, we confirmed the beneficial effects of GbE in alleviating hypercholesterolemia, inflammation and atherosclerosis in Ldlr^-/- mice, which were fed 12 weeks of Western diet (WD). Moreover, 16S rRNA sequencing revealed that GbE treatment reshaped the WD-perturbed intestinal microbiota, particularly decreased the Firmicutes/Bacteroidetes ratio and elevated the abundance of Akkermansia, Alloprevotella, Alistipes, and Parabacteroides. Furthermore, GbE treatment downregulated the intestinal transcriptional levels of proinflammatory cytokines and enhanced the expression of tight junction proteins, exerting the roles of attenuating the intestinal inflammation as well as repairing the gut barrier. Meanwhile, the targeted metabolomic analysis displayed that GbE treatment significantly reversed the dysfunction of the microbial metabolic phenotypes, including promoting the production of short chain fatty acids, indole-3-acetate and secondary bile acids, which were correlated with the atherosclerotic plaque areas. Finally, we confirmed GbE-altered gut microbiota was sufficient to alleviate atherosclerosis by fecal microbiota transplantation. In summary, our findings provide important insights into the pharmacological mechanism underlying the antiatherogenic efficacy of GbE.

Discrimination of Adulterated Ginkgo Biloba Products Based on 2T2D Correlation Spectroscopy in UV-Vis Range

Ginkgo biloba is a popular medicinal plant widely used in numerous herbal products, including food supplements. Due to its popularity and growing economic value, G. biloba leaf extract has become the target of economically motivated adulterations. There are many reports about the poor quality of ginkgo products and their adulteration, mainly by adding flavonols, flavonol glycosides, or extracts from other plants. In this work, we developed an approach using two-trace two-dimensional correlation spectroscopy (2T2D COS) in UV-Vis range combined with multilinear principal component analysis (MPCA) to detect potential adulteration of twenty G. biloba food supplements. UV-Vis spectral data are obtained for 80% methanol and aqueous extracts in the range of 245–410 nm. Three series of two-dimensional correlation spectra were interpreted by visual inspection and using MPCA. The proposed relatively quick and straightforward approach successfully differentiated supplements adulterated with rutin or those lacking ginkgo leaf extract. Supporting information about adulteration was obtained from the difference between the DPPH radical scavenging capacity of both extracts and from chromatographic (HPLC-DAD) fingerprints of methanolic samples.

Ginkgo biloba leaf extract suppresses intestinal human breast cancer resistance protein expression in mice: Correlation with gut microbiota

In this study, we investigated the effects of treatment with Gingko biloba leaf extract (GLE) on intestinal transporter expression and gut microbiota composition in mice and the correlation between intestinal transporter expression and gut microbiota composition in mice. When GLE was orally administered to mice, intestinal BCRP expression was significantly suppressed. Pharmacokinetic studies showed that the maximum plasma concentration and area under the curve values of sulfasalazine were increased more than twice by treatment with GLE compared with those in the control group. GLE treatment significantly decreased the populations of Proteobacteria and Deferribacteres at the phylum level. Correlation analysis showed that BCRP expression was positively or negatively correlated with the composition of gut bacteria. In Caco-2 cells, GLE treatment did not affect BCRP expression, but treatment with the lysates of GLE-treated mouse feces significantly suppressed BCRP expression. These findings demonstrate that the suppression of intestinal BCRP expression following GLE treatment may occur through modulation of the gut microbiota composition. Thus, the present study suggests that modulation of gut microbiota composition may cause drug transporter-mediated herb-drug interactions.

Strategies for the use of Ginkgo biloba extract, EGb 761® , in the treatment and management of mild cognitive impairment in Asia: Expert consensus

BACKGROUND

Mild cognitive impairment (MCI) is a neurocognitive state between normal cognitive aging and dementia, with evidence of neuropsychological changes but insufficient functional decline to warrant a diagnosis of dementia. Individuals with MCI are at increased risk for progression to dementia; and an appreciable proportion display neuropsychiatric symptoms (NPS), also a known risk factor for dementia. Cerebrovascular disease (CVD) is thought to be an underdiagnosed contributor to MCI/dementia. The Ginkgo biloba extract, EGb 761® , is increasingly being used for the symptomatic treatment of cognitive disorders with/without CVD, due to its known neuroprotective effects and cerebrovascular benefits.

AIMS

To present consensus opinion from the ASian Clinical Expert group on Neurocognitive Disorders (ASCEND) regarding the role of EGb 761® in MCI.

MATERIALS & METHODS

The ASCEND Group reconvened in September 2019 to present and critically assess the current evidence on the general management of MCI, including the efficacy and safety of EGb 761® as a treatment option.

RESULTS

EGb 761® has demonstrated symptomatic improvement in at least four randomized trials, in terms of cognitive performance, memory, recall and recognition, attention and concentration, anxiety, and NPS. There is also evidence that EGb 761® may help delay progression from MCI to dementia in some individuals.

DISCUSSION

EGb 761® is currently recommended in multiple guidelines for the symptomatic treatment of MCI. Due to its beneficial effects on cerebrovascular blood flow, it is reasonable to expect that EGb 761® may benefit MCI patients with underlying CVD.

CONCLUSION

As an expert group, we suggest it is clinically appropriate to incorporate EGb 761® as part of the multidomain intervention for MCI.

Advances in the chemical constituents and chemical analysis of Ginkgo biloba leaf, extract, and phytopharmaceuticals

Ginkgo biloba leaf (GBL) is an important botanical drug that can be used for treating many diseases. This review summarizes the reported chemical constituents from GBL or Ginkgo biloba extract (GBE) to date, as well as the recent advances in the extraction, purification, qualitative and quantitative analysis methods (from 2015 to 2020). To date, about 110 flavonoids have been reported to have unambiguous structures, including flavonol and its glycosides, flavone and its glycosides, flavanone and its glycosides, isoflavone and its glycosides, flavan-3-ols, bioflavonoids, and biginkgosides. In recent years, in addition to new flavonoids, new terpenoids and lignan have been also isolated from GBL. Further, several extraction and purification methods have been described and compared. Quantitative analysis of the constituents have been mainly carried out by high-performance liquid chromatography with different detector methods. Many studies have focused on variations of compounds contents in GBL from different regions, tree ages, or collection times, which provide references for the selection of GBL. Liquid chromatography-mass spectrometry coupled with activity assay methods were used to on-line screen the bioactive compounds from GBL or its phytopharmaceuticals. The application of other analytical technologies such as MS imaging, supercritical fluid chromatography, capillary electrophoresis, quantitative nuclear magnetic resonance, and spectroscopy, has also been discussed. This review of the chemical constituents and analytical methods of Ginkgo will provide a reference for the research on the quality control and discovery of effective constituents for GBL and its related phytopharmaceuticals.

Treatment of dementia and mild cognitive impairment with or without cerebrovascular disease: Expert consensus on the use of Ginkgo biloba extract, EGb 761®

Background

The Ginkgo biloba special extract, EGb 761^® has been widely used in the treatment of neuropsychiatric disorders, including Alzheimer’s disease (AD).

Methods

To guide clinical practice in the Asian region, the Asian Clinical Expert Group on Neurocognitive Disorders compiled evidence‐based consensus recommendations regarding the use of EGb 761^® in neurocognitive disorders with/without cerebrovascular disease.

Results

Key randomized trials and robust meta‐analyses have demonstrated significant improvement in cognitive function, neuropsychiatric symptoms, activities of daily living (ADL) and quality of life with EGb 761^®versus placebo in patients with mild‐to‐moderate dementia. In those with mild cognitive impairment (MCI), EGb 761^® has also demonstrated significant symptomatic improvement versus placebo. World Federation of Societies of Biological Psychiatry guidelines list EGb 761^® with the same strength of evidence as acetylcholinesterase inhibitors and N‐methyl‐D‐aspartate (NMDA) antagonists e.g. memantine (Grade 3 recommendation; Level B evidence). Only EGb 761^® had Level B evidence in improving cognition, behaviour, and ADL in both AD and vascular dementia patients. Safety analyses show EGb 761^® to have a positive risk‐benefit profile. While concerns have been raised regarding a possible increased bleeding risk, several randomized trials and two meta‐analyses have not supported this association.

Conclusions

The Expert Group foresee an important role for EGb 761^®, used alone or as an add‐on therapy, in the treatment of MCI and dementias, particularly when patients do not derive benefit from acetylcholinesterase inhibitors or NMDA antagonists. EGb 761^® should be used in alignment with local clinical practice guidelines.

Dietary natural products as emerging lipoprotein(a)-lowering agents

Elevated plasma lipoprotein(a) (Lp(a)) levels are associated with an increased risk of cardiovascular disease (CVD). Hitherto, niacin has been the drug of choice to reduce elevated Lp(a) levels in hyperlipidemic patients but its efficacy in reducing CVD outcomes has been seriously questioned by recent clinical trials. Additional drugs may reduce to some extent plasma Lp(a) levels but the lack of a specific therapeutic indication for Lp(a)-lowering limits profoundly reduce their use. An attractive therapeutic option is natural products. In several preclinical and clinical studies as well as meta-analyses, natural products, including l-carnitine, coenzyme Q ₁₀ , and xuezhikang were shown to significantly decrease Lp(a) levels in patients with Lp(a) hyperlipoproteinemia. Other natural products, such as pectin, Ginkgo biloba, flaxseed, red wine, resveratrol and curcuminoids can also reduce elevated Lp(a) concentrations but to a lesser degree. In conclusion, aforementioned natural products may represent promising therapeutic agents for Lp(a) lowering.

Natural plant products in treatment of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a severe disease characterized by progressive remodeling of distal pulmonary arteries and persistent elevation of pulmonary vascular resistance (PVR), which leads to right ventricular dysfunction, heart failure, and eventually death. Although treatment responsiveness for this disease is improving, it continues to be a life-threatening condition. With the clinical efficacy of natural plant products being fully confirmed by years of practice, more and more recognition and attention have been obtained from the international pharmaceutical industry. Moreover, studies over the past decades have demonstrated that drugs derived from natural plants show unique advantages and broad application prospects in PAH treatment, not to mention the historical application of Chinese traditional medicine in cardiopulmonary diseases. In this review, we focus on summarizing natural plant compounds with therapeutic properties in PAH, according to the extracts, fractions, and pure compounds from plants into categories, hoping it to be helpful for basic research and clinical application.

Comparative efficacy of Chinese herbal injections for treating acute cerebral infarction: a network meta-analysis of randomized controlled trials

Background

Chinese herbal injections (CHIs) are prepared by extracting and purifying effective substances from herbs (or decoction pieces) using modern scientific techniques and methods. CHIs combined with aspirin + anticoagulants + dehydrant + neuroprotectant (AADN) are believed to be effective for the treatment of acute cerebral infarction (ACI). However, no randomized controlled trial (RCT) has been performed to directly compare the efficacies of different regimens of CHIs. Therefore, we performed a systematic review and network meta-analysis (NMA) to compare the efficacies of different regimens of CHIs for ACI.

Methods

We conducted an overall and systematic retrieval from literature databases of RCTs focused on the use of CHIs to treat ACI up to June 2016. We used the Cochrane Handbook version 5.1.0 and CONSORT statement to assess the risk of bias. The data were analyzed using STATA 13.0 and WinBUGS 1.4.3 software.

Results

Overall, 64 studies with 6225 participants involving 15 CHIs were included in the NMA. In terms of the markedly effective rate, Danhong (DH) + AADN had the highest likelihood of being the best treatment. In terms of the improvement of neurological impairment, Shuxuening (SXN) + AADN had the highest likelihood of being the best treatment. Considering two outcomes, injections of SXN, Yinxingdamo (YXDM), DH, Shuxuetong (SXT), HongHuaHuangSeSu (HHHSS), DengZhanXiXin (DZXX) and Shenxiong glucose (SX) plus AADN were the optimum treatment regimens for ACI, especially SXN + AADN and YXDM + AADN.

Conclusions

Based on the NMA, SXN, YXDM, DH, SXT, HHHSS, DZXX and SX plus AADN showed the highest probability of being the best treatment regimens. Due to the limitations of the present study, our findings should be verified by well-designed RCTs.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2178-9) contains supplementary material, which is available to authorized users.

Effect of bilayer charge on lipoprotein lipid exchange

Lipoproteins play a key role in the onset and development of atherosclerosis, the formation of lipid plaques at blood vessel walls. The plaque formation, as well as subsequent calcification, involves not only endothelial cells but also connective tissue, and is closely related to a wide range of cardiovascular syndromes, that together constitute the number one cause of death in the Western World. High (HDL) and low (LDL) density lipoproteins are of particular interest in relation to atherosclerosis, due to their protective and harmful effects, respectively. In an effort to elucidate the molecular mechanisms underlying this, and to identify factors determining lipid deposition and exchange at lipid membranes, we here employ neutron reflection (NR) and quartz crystal microbalance with dissipation (QCM-D) to study the effect of membrane charge on lipoprotein deposition and lipid exchange. Dimyristoylphosphatidylcholine (DMPC) bilayers containing varying amounts of negatively charged dimyristoylphosphatidylserine (DMPS) were used to vary membrane charge. It was found that the amount of hydrogenous material deposited from either HDL or LDL to the bilayer depends only weakly on membrane charge density. In contrast, increasing membrane charge resulted in an increase in the amount of lipids removed from the supported lipid bilayer, an effect particularly pronounced for LDL. The latter effects are in line with previously reported observations on atherosclerotic plaque prone regions of long-term hyperlipidaemia and type 2 diabetic patients, and may also provide some molecular clues into the relation between oxidative stress and atherosclerosis.

Advances in the Studies of Ginkgo Biloba Leaves Extract on Aging-Related Diseases

The prevalence of degenerative disorders in public health has promoted in-depth investigations of the underlying pathogenesis and the development of new treatment drugs. Ginkgo biloba leaves extract (EGb) is obtained from Ginkgo biloba leaves and has been used for thousands of years. In recent decades, both basic and clinical studies have established the effects of EGb. It is widely used in various degenerative diseases such as cerebrovascular disease, Alzheimer's disease, macroangiopathy and more. Here, we reviewed several pharmacological mechanisms of EGb, including its antioxidant properties, prevention of mitochondrial dysfunctions, and effect on apoptosis. We also described some clinical applications of EGb, such as its effect on neuro and cardiovascular protection, and anticancer properties. The above biological functions of EGb are mainly focused on aging-related disorders, but its effect on other diseases remains unclear. Thus, through this review, we aim to encourage further studies on EGb and discover more potential applications.

A systematic review of the pharmacokinetic and pharmacodynamic interactions of herbal medicine with warfarin

Objectives

The aim of this study was to systematically review data regarding pharmacokinetic (PK)-pharmacodynamic (PD) parameters from randomized controlled trials relating to interactions between herbal medicines and warfarin.

Methods

Three electronic databases were searched to identify relevant trials. Two reviewers independently performed the study selection and data extraction. The risk of bias and reporting quality were also assessed independently by two reviewers using the Cochrane risk of bias tool and the consolidated standards of reporting trials (CONSORT). Outcomes were measured for all reported PK-PD parameters and adverse events.

Results

Nine randomized controlled trials met our inclusion criteria. Most of the included studies were unclear regarding the risk of bias and had a low quality of methodology. Using CONSORT, the reporting percentages for the articles ranged from 36.5% to 61.5% and the mean percentage for all articles was 45.6%. St John’s wort and echinacea affected the PK parameters of warfarin. Ginseng, ginger, garlic, and cranberry had no significant effect on the PK parameters. American ginseng altered the PD parameters of warfarin. St John’s wort, ginseng, Korea red ginseng, ginkgo, ginger, garlic, aged garlic, and echincea did not significantly alter the PD parameters. Studies of ginkgo and cranberry showed conflicting results on the PK parameters and PD parameters, respectively. The incidence of adverse events in all trials was low and no major adverse events were reported.

Conclusions

It was difficult to determine whether ten herbal medicines had significant effects on the PK-PD parameters of warfarin. Low quality of evidence, different compounds within and different compositions of the herbs, and methodological limitations of the crossover study, which is a clinical study in which subjects receive a sequence of different interventions, made it difficult to form conclusions. Additional studies that remedy these vulnerabilities are necessary to verify these results.

Lipoprotein binding to anionic biopolyelectrolytes and the effect of glucose on nanoplaque formation in arteriosclerosis and Alzheimer's disease

Arteriosclerosis with its clinical sequelae (cardiac infarction, stroke, peripheral arterial occlusive disease) and vascular/Alzheimer dementia not only result in far more than half of all deaths but also represent dramatic economic problems. The reason is, among others, that diabetes mellitus is an independent risk factor for both disorders, and the number of diabetics strongly increases worldwide. More than one-half of infants in the first 6months of life have already small collections of macrophages and macrophages filled with lipid droplets in susceptible segments of the coronary arteries. On the other hand, the authors of the Bogalusa Heart Study found a strong increase in the prevalence of obesity in childhood that is paralleled by an increase in blood pressure, blood lipid concentration, and type 2 diabetes mellitus. Thus, there is a clear linkage between arteriosclerosis/Alzheimer's disease on the one hand and diabetes mellitus on the other hand. Furthermore, it has been demonstrated that distinct apoE isoforms on the blood lipids further both arteriosclerotic and Alzheimer nanoplaque formation and therefore impair flow-mediated vascular reactivity as well. Nanoplaque build-up seems to be the starting point for arteriosclerosis and Alzheimer's disease in their later full clinical manifestation. In earlier work, we could portray the anionic biopolyelectrolytes syndecan/perlecan as blood flow sensors and lipoprotein receptors in cell membrane and vascular matrix. We described extensively molecular composition, conformation, form and function of the macromolecule heparan sulfate proteoglycan (HS-PG). In two supplementary experimental settings (ellipsometry, myography), we utilized isolated HS-PG for in vitro nanoplaque investigations and isolated human coronary artery segments for in vivo tension measurements. With the ellipsometry-based approach, we were successful in establishing a direct connection on a molecular level between diabetes mellitus on the one side and arteriosclerosis/Alzheimer's disease on the other side. Application of glucose at a concentration representative for diabetics and leading to glycation of proteins and lipids, entailed a significant increase in arteriosclerotic and Alzheimer nanoplaque formation. IDLapoE4/E4 was by far superior to IDLapoE3/E3 in plaque build-up, both in diabetic and non-diabetic patients. Recording vascular tension of flow-dependent reactivity in blood substitute solution and under application of different IDLapoE isoforms showed an impaired vasorelaxation for pooled IDL and IDLapoE4/E4, thus confirming the ellipsometric investigations. Incubation in IDLapoE0/E0 (apoE "knockout man"), however, resulted in a massive flow-mediated contraction, also complemented by strongly aggregated nanoplaques. In contrast, HDL was shown to present a powerful protection against nanoplaque formation on principle, both in the in vitro model and the in vivo scenario on the endothelial cell membrane. The competitive interplay with LDL is highlighted through the flow experiment, where flow-mediated, HDL-induced vasodilatation remains untouched by additional incubation with LDL. This is due to the four times higher affinity for the proteoglycan receptor of HDL as compared to LDL. Taken together, the studies demonstrate that while simplistic, the ellipsometry approach and the endothelial-mimicking proteoglycan-modified surfaces provide information on the initial steps of lipoprotein-related plaque formation, which correlates with findings on endothelial cells and blood vessels, and afford insight into the role of lipoprotein deposition and exchange phenomena at the onset of these pathophysiologies.

Polydopamine-assisted deposition of heparin for selective adsorption of low-density lipoprotein

Low-density lipoprotein (LDL) is the main carrier of blood cholesterol, with elevated levels of LDL increasing the risk of atherosclerosis.

Transcriptome analysis of Ginkgo biloba kernels

Ginkgo biloba is a dioecious species native to China with medicinally and phylogenetically important characteristics; however, genomic resources for this species are limited. In this study, we performed the first transcriptome sequencing for Ginkgo kernels at five time points using Illumina paired-end sequencing. Approximately 25.08-Gb clean reads were obtained, and 68,547 unigenes with an average length of 870 bp were generated by de novo assembly. Of these unigenes, 29,987 (43.74%) were annotated in publicly available plant protein database. A total of 3,869 genes were identified as significantly differentially expressed, and enrichment analysis was conducted at different time points. Furthermore, metabolic pathway analysis revealed that 66 unigenes were responsible for terpenoid backbone biosynthesis, with up to 12 up-regulated unigenes involved in the biosynthesis of ginkgolide and bilobalide. Differential gene expression analysis together with real-time PCR experiments indicated that the synthesis of bilobalide may have interfered with the ginkgolide synthesis process in the kernel. These data can remarkably expand the existing transcriptome resources of Ginkgo, and provide a valuable platform to reveal more on developmental and metabolic mechanisms of this species.

Combined lowering of low grade systemic inflammation and insulin resistance in metabolic syndrome patients treated with Ginkgo biloba

In a clinical pilot study with eleven metabolic syndrome patients, a simultaneous decrease in hs-CRP from 8.85 ± 4.09 to 4.92 ± 2.51 mg/L (-44.4%) (p < 0.0436) and HOMA-IR from 3.07 ± 0.63 to 2.60 ± 0.51 mU/L × mg/dL (-15.3%) (p < 0.0120) as well as a beneficial change of arteriosclerotic, inflammatory and oxidative stress biomarkers were detected after 2-month treatment with Ginkgo biloba. Furthermore, both IL-6 (-12.9%, p < 0.0407) and nanoplaque formation (-14.3%, p < 0.0077) were additionally reduced. According to a large clinical trial elucidating the importance of insulin resistance and low-grade systemic inflammation for cardiovascular disease and overall mortality risk, these data might indicate a CVD/total mortality risk reduction.

Anionic biopolyelectrolytes of the syndecan/perlecan superfamily: physicochemical properties and medical significance

In the review article presented here, we demonstrate that the connective tissue is more than just a matrix for cells and a passive scaffold to provide physical support. The extracellular matrix can be subdivided into proteins (collagen, elastin), glycoconjugates (structural glycoproteins, proteoglycans) and glycosaminoglycans (hyaluronan). Our main focus rests on the anionic biopolyelectrolytes of the perlecan/syndecan superfamily which belongs to extracellular matrix and cell membrane integral proteoglycans. Though the extracellular domain of the syndecans may well be performing a structural role within the extracellular matrix, a key function of this class of membrane intercalated proteoglycans may be to act as signal transducers across the plasma membrane and thus be more appropriately included in the group of cell surface receptors. Nevertheless, there is a continuum in functions of syndecans and perlecans, especially with respect to their structural role and biomedical significance. HS/CS proteoglycans are receptor sites for lipoprotein binding thus intervening directly in lipid metabolism. We could show that among all lipoproteins, HDL has the highest affinity to these proteoglycans and thus instals a feedforward forechecking loop against atherogenic apoB100 lipoprotein deposition on surface membranes and in subendothelial spaces. Therefore, HDL is not only responsible for VLDL/IDL/LDL cholesterol exit but also controls thoroughly the entry. This way, it inhibits arteriosclerotic nanoplaque formation. The ternary complex 'lipoprotein receptor (HS/CS-PG) - lipoprotein (LDL, oxLDL, Lp(a)) - calcium' may be interpreted as arteriosclerotic nanoplaque build-up on the molecular level before any cellular reactivity, possibly representing the arteriosclerotic primary lesion combined with endothelial dysfunction. With laser-based ellipsometry we could demonstrate that nanoplaque formation is a Ca(2+)-driven process. In an in vitro biosensor application of HS-PG coated silica surfaces we tested nanoplaque formation and size in clinical trials with cardiovascular high-risk patients who underwent treatment with ginkgo or fluvastatin. While ginkgo reduced nanoplaque formation (size) by 14.3% (23.4%) in the isolated apoB100 lipid fraction at a normal blood Ca(2+) concentration, the effect of the statin with a reduction of 44.1% (25.4%) was more pronounced. In addition, ginkgo showed beneficial effects on several biomarkers of oxidative stress and inflammation. Besides acting as peripheral lipoprotein binding receptor, HS/CS-PG is crucially implicated in blood flow sensing. A sensor molecule has to fulfil certain mechanochemical and mechanoelectrical requirements. It should possess viscoelastic and cation binding properties capable of undergoing conformational changes caused both mechanically and electrostatically. Moreover, the latter should be ion-specific. Under no-flow conditions, the viscoelastic polyelectrolyte at the endothelium - blood interface assumes a random coil form. Blood flow causes a conformational change from the random coil state to the directed filament structure state. This conformational transition effects a protein unfurling and molecular elongation of the GAG side chains like in a 'stretched' spring. This configuration is therefore combined with an increase in binding sites for Na(+) ions. Counterion migration of Na(+) along the polysaccharide chain is followed by transmembrane Na(+) influx into the endothelial cell and by endothelial cell membrane depolarization. The simultaneous Ca(2+) influx releases NO and PGI2, vasodilatation is the consequence. Decrease in flow reverses the process. Binding of Ca(2+) and/or apoB100 lipoproteins (nanoplaque formation) impairs the flow sensor function. The physicochemical and functional properties of proteoglycans are due to their amphiphilicity and anionic polyelectrolyte character. Thus, they potently interact with cations, albeit in a rather complex manner. Utilizing (23)Na(+) and (39)K(+) NMR techniques, we could show that, both in HS-PG solutions and in native vascular connective tissue, the mode of interaction for monovalent cations is competition. Mg(2+) and Ca(2+) ions, however, induced a conformational change leading to an increased allosteric, cooperative K(+) and Na(+) binding, respectively. Since extracellular matrices and basement membranes form a tight-fitting sheath around the cell membrane of muscle and Schwann cells, in particular around sinus node cells of the heart, and underlie all epithelial and endothelial cell sheets and tubes, a release of cations from or an adsorption to these polyanionic macromolecules can transiently lead to fast and drastic activity changes in these tiny extracellular tissue compartments. The ionic currents underlying pacemaker and action potential of sinus node cells are fundamentally modulated. Therefore, these polyelectrolytic ion binding characteristics directly contribute to and intervene into heart rhythm.

[Clinical studies in peripheral arterial occlusive disease: update from the aspects of a meta-narrative review]

BACKGROUND

Atherosclerosis is a systemic disease. Its association with the metabolic syndrome requires a multimodal therapy setting, to alleviate symptoms and for primary and secondary prevention. In the planning of the therapy, information about evidence of the interventions and a rationale for reasonable combinations are important.

METHOD

For compiling a meta-narrative review (MNR) on the evidence of complementary and conventional pharmaco-therapy in peripheral arterial occlusive disease (PAOD), the literature was searched for meta-analyses of randomized controlled trials (RCTs). These were evaluated taking into account network-pharmacological aspects and research parameters.

RESULTS

4 suitable meta-analyses were found. In comparison to placebo, treatments with verum showed a significant improvement of the maximum walking distance of 63.5 m (95% confidence interval (CI) 27.11-99.91 m; Padma 28, Tibetan Formula), 41.3 m (95% CI -7.1-89.7 m; cilostazol, phosphodiesterase IIl inhibitor), 43.8 m (95% CI 14.1-73.6 m; pentoxifylline, rheological drug), and 71.2 m (95% CI 13.3-129.0 m; naftidrofuryl, rheological drug). Only for Padma 28, clinical relevance, defined as an increase of the maximum walking distance by >100 m, was analyzed and reached by 18.2% of the verum and 2.1% of the placebo patients (odds ratio 10; 95% CI 3.03-33.33). 1 conventional and 1 complementary drug additionally showed to have significant pleiotropic effects (Padma 28 and cilostazol (e.g. reduction of triglycerides)).

CONCLUSIONS

According to meta-analytic evidence, naftidrofuryl and Padma 28 show clinically relevant efficacy for the treatment of early stages of PAOD. The extent to which the theoretically possible combination of different drugs contributes to improve the systemic disease under a network-pharmacological rationale remains to be shown in a multi-armed RCT.

Ginkgo suppresses atherosclerosis through downregulating the expression of connexin 43 in rabbits

INTRODUCTION

Ginkgo biloba extract (GBE) EGb761 is widely used for cardiovascular prevention. Here, we investigated the effects of GBE on atherosclerotic lesion development in rabbits with a high-fat diet.

MATERIAL AND METHODS

Forty New Zealand white male rabbits were randomly divided into four groups. The first two were the normal diet group (C) and the high-fat group (HF). The remaining two groups were those who received a high cholesterol diet supplemented with either the standard drug (simvastatin 2 mg/kg/day) or GBE (3 mg/kg/day). At 12 weeks, histopathological and chemical analyses were performed.

RESULTS

Plasma lipid measurement showed that GBE inhibited high-fat diet-induced increase of serum triglyceride (TG), total cholesterol (TC), and low density lipoprotein cholesterol (LDL-C) by 59.1% (0.9 ±0.2 4 mmol/l vs. 2.2 ±0.4 mmol/l), 18.2% (31.1 ±1.4 mmol/l vs. 38.0 ±0.4 mmol/l) and 15% (28.9 ±1.3 mmol/l vs. 34.0±1.0 mmol/l), respectively, at 12 weeks (p < 0.01). The en face Sudan IV-positive lesion area of the aorta in the GBE group (51.7 ±3.1%) was significantly lower compared with that in the HF group (88.2 ±2.2%; p < 0.01). The mean atherosclerotic lesion area of the GBE group was reduced by 53.2% compared with the HF group (p < 0.01). Immunohistochemistry and western blot analysis showed that GBE markedly suppressed high-fat diet-induced upregulation of connexin 43 (Cx43) in rabbits (p < 0.01).

CONCLUSIONS

Thus, our study revealed that GBE prevented atherosclerosis progress through modulating plasma lipid, suppressing atherosclerotic lesion development, and attenuating the expression of Cx43 protein.

Ginkgo biloba extract reduces high-glucose-induced endothelial reactive oxygen species generation and cell adhesion molecule expression by enhancing HO-1 expression via Akt/eNOS and p38 MAP kinase pathways

AIM

Hyperglycemia is one of the major risk factors leading to vascular complications in clinical diabetes mellitus. Ginkgo biloba extract (GBE), an antioxidant herbal medicine, possesses anti-inflammatory effects. We examined whether GBE can reduce high glucose-induced endothelial adhesiveness to monocytes, an in vitro sign mimicking in vivo early atherogenesis, through selective regulation of heme oxygenase (HO)-1 expression.

METHODS

Human aortic endothelial cells (HAECs) were cultured with normal glucose or high glucose (25 mM) for 4 days and subsequently combined with GBE (EGb761, Dr. Willmar Schwabe, Karlsruhe, Germany) treatment in the last 18 h of the 4-day period. The endothelial reactive oxygen species (ROS) generation, adhesion molecule expression and the adhesiveness to monocytes were examined. The specific signal pathways such as HO-1 were also examined.

RESULTS

High glucose increased ROS generation, adhesion molecule expression and the adhesiveness to monocytes in HAECs. These high glucose-induced phenomena could be suppressed by GBE (100 μg/ml)-induced HO-1 expression in a dose-dependent and time-dependent manner. In addition, jun N-terminal kinases inhibitor or phosphoinositide 3 kinase inhibitor could reduce GBE-induced HO-1 expression. Furthermore, HO-1 inhibitor, HO-1 siRNA, endothelial nitric oxide synthase (eNOS) siRNA, or nuclear factor erythroid 2-related factor (Nrf) 2 siRNA blocked the cytoprotective effects of GBE. Meanwhile, p38/mitogen-activated protein kinase (MAPK) inhibitor could also reduce the effects of GBE on HO-1 induction.

CONCLUSION

GBE could reduce high glucose-induced endothelial adhesion via enhancing HO-1 expression through the Akt/eNOS and p38/MAPK pathways. Our findings suggest a potential strategy targeting on HO-1 induction by GBE for endothelial protection in the presence of high glucose such as that in diabetes mellitus.

Ginkgo biloba extract (GbE) enhances the anti-atherogenic effect of cilostazol by inhibiting ROS generation

In this study, the synergistic effect of 6-[4-(1-cyclohexyl- 1H-tetrazol-5-yl) butoxy]-3,4-dihydro-2(1H )-quinolinone (cilostazol) and Ginkgo biloba extract (GbE) was examined in apolipoprotein E (ApoE) null mice. Co-treatment with GbE and cilostazol synergistically decreased reactive oxygen species (ROS) production in ApoE null mice fed a high-fat diet. Co-treatment resulted in a significantly decreased atherosclerotic lesion area compared to untreated ApoE mice. The inflammatory cytokines and adhesion molecules such as monocyte chemoattractant-1 (MCP-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and VCAM-1 which can initiate atherosclerosis were significantly reduced by the co-treatment of cilostazol with GbE. Further, the infiltration of macrophages into the intima was decreased by co-treatment. These results suggest that co-treatment of GbE with cilostazol has a more potent anti-atherosclerotic effect than treatment with cilostazol alone in hyperlipidemic ApoE null mice and could be a valuable therapeutic strategy for the treatment of atherosclerosis.

A new ginkgo fresh plant extract increases microcirculation and radical scavenging activity in elderly patients

INTRODUCTION

The authors investigated whether a new ginkgo biloba (ginkgo) fresh plant extract had a positive effect on microcirculation in the skin and liver of elderly individuals, and whether the extract had antioxidative properties in vivo.

METHODS

In a monocentric, controlled clinical trial with 32 elderly patients, 16 patients received three 90 mg ginkgo extract tablets twice daily for 30 days, and 16 patients acted as untreated controls. On days 0, 10, 20, and 30, microcirculatory parameters were measured using intravital microscopy in combination with reflection spectrometry, and the amount of reduced glutathione in the liver.

RESULTS

This new ginkgo fresh plant extract significantly increased the number of blood cell-perfused nodal points, the venular streaming flow, and the local hematocrit in treated participants compared to control participants and compared to values on day 0. The ginkgo preparation also increased microcirculation in the liver, and possessed antioxidative properties that resulted in significant increases in the amount of the radical scavenger glutathione in treated participants.

CONCLUSION

The new ginkgo fresh plant extract increased the microcirculation significantly, and at the same time improved the radical scavenging capacity in elderly patients and was very well tolerated. This extract is an interesting adjuvant treatment option for patients suffering from impaired microcirculation and improves mechanisms which inhibit an accelerated expression of atherosclerosis.

Functional genomics of a living fossil tree, Ginkgo, based on next-generation sequencing technology

Ginkgo biloba is monotypic species native to China and has old, dioecious, medicinally important characteristics. The functional genes related to these characteristics have not been effectively explored due to a limited number of expressed sequence tags (ESTs) from Ginkgo. To discover novel functional genes efficiently and to understand the development of a living fossil tree, Ginkgo, we used massive parallel pyrosequencing on the Roche 454 GS FLX Titanium platform to generate 64 057 ESTs. The ESTs combined with the 21 590 Ginkgo ESTs in genbank were assembled into 22 304 unique putative transcripts, in which 13 922 novel unique putative transcripts were identified by 454 sequencing. After being assigned to putative functions with Gene Ontology terms, a detailed view of the Ginkgo biological systems was displayed, including characterization of unique putative transcripts with homology to known key enzymes and transcription factors involved in ginkgolide/bilobalide and flavonoid biosynthetic pathways, as well as unique putative transcripts related to development, response to disease and defence. The fact that three full-length Ginkgo genes encoding key enzymes were found and cloned, suggests that high-throughput sequencing technology is superior to traditional gene-by-gene approach in discovery of genes. Additionally, a total of 204 simple sequence repeat motifs were detected. Our study not only lays the foundations for transcriptome-led studies in biosynthetic mechanisms, but also contributes significantly to the understanding of functional genomics and development in non-model plants.

Mechanistic roles of lipoprotein lipase and sphingomyelinase in low density lipoprotein aggregation

The initiation of atherosclerosis involves retention of colloidal atherogenic lipoproteins, primarily low density lipoprotein (LDL), in the arterial intima. This retention occurs when LDL binds to smooth muscle cell extracellular matrix (SMC ECM), and is enhanced by lipoprotein lipase (LpL) and sphingomyelinase (Smase). Here we use a fluorescence assay and dynamic light scattering to study the individual and combined effects of these two enzymes on LDL aggregation. Our results show: (1) LpL is self-sufficient to induce LDL aggregation with aggregate sizes up to ~400 nm; (2) Smase induces LDL aggregation due to generation of ceramide and subsequent hydrophobic interactions; (3) Smase hydrolysis of LpL-induced LDL aggregates does not cause further aggregation and results in a ~3-fold diminished production of ceramide, while LpL treatment of Smase-induced aggregates does enhance aggregation; (4) The simultaneous addition of LpL and Smase causes increased variability in aggregation with final sizes ranging from 50 to 110 nm. Our data suggest a new proatherogenic function for LpL, namely, bridging between LDL particles causing their aggregation and consequently enhanced retention by SMC ECM. The mechanism of LpL-and-Smase-mediated LDL aggregation and binding to SMC ECM provides specific points of intervention to design novel effective antiatherogenic therapeutics.

EGb761, a Ginkgo biloba extract, is effective against atherosclerosis in vitro, and in a rat model of type 2 diabetes

BACKGROUND

EGb761, a standardized Ginkgo biloba extract, has antioxidant and antiplatelet aggregation and thus might protect against atherosclerosis. However, molecular and functional properties of EGb761 and its major subcomponents have not been well characterized. We investigated the effect of EGb761 and its major subcomponents (bilobalide, kaemferol, and quercetin) on preventing atherosclerosis in vitro, and in a rat model of type 2 diabetes.

METHODS AND RESULTS

EGb761 (100 and 200 mg/kg) or normal saline (control) were administered to Otsuka Long-Evans Tokushima Fatty rats, an obese insulin-resistant rat model, for 6 weeks (from 3 weeks before to 3 weeks after carotid artery injury). Immunohistochemical staining was performed to investigate cell proliferation and apoptosis in the injured arteries. Cell migration, caspase-3 activity and DNA fragmentation, monocyte adhesion, and ICAM-1/VCAM-1 levels were explored in vitro. Treatment with EGb761 dose-dependently reduced intima-media ratio, proliferation of vascular smooth muscle cells (VSMCs) and induced greater apoptosis than the controls. Proliferation and migration of VSMCs in vitro were also decreased by the treatment of EGb761. Glucose homeostasis and circulating adiponectin levels were improved, and plasma hsCRP concentrations were decreased in the treatment groups. Caspase-3 activity and DNA fragmentation increased while monocyte adhesion and ICAM-1/VCAM-1 levels decreased significantly. Among subcomponents of EGb761, kaemferol and quercetin reduced VSMC migration and increased caspase activity.

CONCLUSIONS

EGb761 has a protective role in the development of atherosclerosis and is a potential therapeutic agent for preventing atherosclerosis.

Optimal therapy for reduction of lipoprotein(a)

WHAT IS KNOWN AND OBJECTIVE

There is a growing body of experimental and clinical evidence for the atherogenic and pro-thrombotic potential of Lipoprotein(a) [Lp(a)], as well as for its causative role in coronary heart disease and stroke. We comment on novel strategies for reducing Lp(a) levels.

COMMENT

Irrespective of the underlying biological mechanisms explaining the athero-thrombotic potential of this lipoprotein, most work has focused on the identification of suitable therapies for hyperlipoproteinemia(a). These include apheresis techniques, nicotinic acid and statins. None of these strategies have been shown to be definitely effective or convenient for the patient and new strategies are being attempted. Promising results are emerging with therapeutic interventions targeting the 'inflammatory pathways' by inhibition of Interleukin-6 (IL-6) signalling with natural compounds (e.g., Ginko biloba) or the IL-6 receptor antibody Tocilizumab. These may both lower Lp(a) and cardiovascular risk of the patients. Besides inhibiting platelet function, antiplatelet therapy with aspirin may also decrease the plasma concentration of Lp(a) and modulate its influence on platelets.

WHAT IS NEW AND CONCLUSION

We highlight the inadequacy of current approaches for lowering Lp(a) and draw attention to novel insights that may lead to better treatment.

Nrf-2 mediated heme oxygenase-1 expression, an antioxidant-independent mechanism, contributes to anti-atherogenesis and vascular protective effects of Ginkgo biloba extract

AIMS

Vascular protective effects of Ginkgo biloba extract (GBE) may involve both antioxidant-related and anti-inflammatory mechanisms. GBE was recently suggested as a heme oxygenase (HO)-1 inducer. The role of HO-1 in anti-atherogenesis and related vascular protective effects of GBE awaited further clarification.

METHODS AND RESULTS

Tumor necrosis factor (TNF)-α was used to stimulate adhesiveness of human aortic endothelial cells (HAECs) to monocytes, an in vitro sign simulating atherogenesis. Pretreatment with GBE reduced TNF-α-stimulated endothelial adhesiveness, which could be attenuated by HO-1 inhibitors ZnPP IX or SnPP IX. GBE increased HO-1 expression and enzyme activity in HAECs. Pretreatment with MAP kinase inhibitor SB203580 significantly reduced GBE-induced HO-1 expression. Furthermore, GBE activated the translocation of the transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2), and increased its binding to the antioxidant response element (ARE) of the HO-1 gene. Pretreatment with PEG-SOD or other antioxidant reagents did not alter GBE-induced endothelial HO-1 expression. In vivo study also showed that GBE treatment could reduce leukocyte adherence to injury arteries, and enhance HO-1 expression in circulating monocytes and in arteries after wire injury, suggesting the in vivo induction of HO-1 by GBE.

CONCLUSION

GBE could inhibit cytokine-induced endothelial adhesiveness by inducing HO-1 expression via the activation of p38 and Nrf-2 pathways, a mechanism in which oxidative stress is not directly involved. GBE might exert its anti-atherogenesis and vascular protective effects by inducing vascular HO-1 expression.

EGb761 ameliorates the formation of foam cells by regulating the expression of SR-A and ABCA1: role of haem oxygenase-1

AIMS

Accumulation of foam cells in the intima is a hallmark of early-stage atherosclerotic lesions. Ginkgo biloba extract (EGb761) has been reported to exert anti-oxidative and anti-inflammatory properties in atherosclerosis, yet the significance and the molecular mechanisms of action of EGb761 in the formation of macrophage foam cells are not fully understood.

METHODS AND RESULTS

Treatment with EGb761 resulted in a dose-dependent decrease in oxidized low-density lipoprotein (oxLDL)-mediated cholesterol accumulation in macrophages, a consequence that was due to a decrease in cholesterol uptake and an increase in cholesterol efflux. Additionally, EGb761 significantly down-regulated the mRNA and protein expression of class A scavenger receptor (SR-A) by decreasing expression of activator protein 1 (AP-1); however, EGb761 increased the protein stability of ATP-binding cassette transporter A1 (ABCA1) by reducing calpain activity without affecting ABCA1 mRNA expression. Small interfering RNA (siRNA) targeting haem oxygenase-1 (HO-1) abolished the EGb761-induced protective effects on the expression of AP-1, SR-A, ABCA1, and calpain activity. Accordingly, EGb761-mediated suppression of lipid accumulation in foam cells was also abrogated by HO-1 siRNA. Moreover, the lesion size of atherosclerosis was smaller in EGb761-treated, apolipoprotein E-deficient mice compared with the vehicle-treated mice, and the expression of HO-1, SR-A, and ABCA1 in aortas was modulated similar to that observed in macrophages.

CONCLUSION

These findings suggest that EGb761 confers a protection from the formation of foam cells by a novel HO-1-dependent regulation of cholesterol homeostasis in macrophages.

Application of GC/MS-based metabonomic profiling in studying the lipid-regulating effects of Ginkgo biloba extract on diet-induced hyperlipidemia in rats

AIM

To evaluate the lipid-regulating effects of extract from Ginkgo biloba leaves (EGB) using pharmacological methods and metabonomic profiling in a rat model of diet-induced hyperlipidemia.

METHODS

EGB was orally administered at a dose level of 40 mg/kg in both the EGB-prevention and -treatment groups. All rat samples obtained were examined for known and potential biomarkers and enzyme activity using commercial assay kits and GC/MS-based metabonomic profiling coupled with principal component analysis (PCA).

RESULTS

The data obtained from the assay kits indicated that EGB reduced total cholesterol and low density lipoprotein cholesterol levels and increased high density lipoprotein cholesterol levels in rat plasma obtained from both the EGB-prevention and -treatment groups compared with those of the diet-induced hyperlipidemia group. EGB also increased the activities of lipoprotein lipase and hepatic lipase and excretion of fecal bile acid in rats from the EGB-prevention and-treatment groups. Using GC/MS-based metabonomic analysis, more than 40 endogenous metabolites were identified in rat plasma. PCA of rat plasma samples obtained using GC/MS produced a distinctive separation of the four treatment groups and sampling points within each group. Metabolic changes during hyperlipidemia formation and improvement resulting from EGB treatment were definitively monitored with PCA score plots. Furthermore, elevated levels of sorbitol, tyrosine, glutamine and glucose, and decreased levels of citric acid, galactose, palmitic acid, arachidonic acid, acetic acid, cholesterol, butyrate, creatinine, linoleate, ornithine and proline, were observed in the plasma of rats treated with EGB.

CONCLUSION

EGB exerts multi-directional lipid-lowering effects on the rat metabonome, including limitation of the absorption of cholesterol, inactivation of HMGCoA and favorable regulation of profiles of essential polyunsaturated fatty acid (EFA). Further experiments are warranted to explore the mechanisms of action underlying the lipid-regulating effects of EGB against hyperlipidemia.

Ginkgolide B suppresses intercellular adhesion molecule-1 expression via blocking nuclear factor-kappaB activation in human vascular endothelial cells stimulated by oxidized low-density lipoprotein

Atherosclerosis is a complex inflammatory arterial disease. Oxidized low-density lipoprotein (ox-LDL) is directly associated with chronic vascular inflammation. In the current study, we tested the hypothesis that ginkgolide B, a component of traditional Chinese herbal medicine for heart disorder, may affect ox-LDL-induced inflammatory responses in human umbilical vein endothelial cells (HUVECs). The results showed that the ox-LDL treatment caused a significantly increase in the expression of intercellular adhesion molecule-1 (ICAM-1) in HUVECs, which was associated with a dramatic augmentation in phosphorylation of IkappaB and relocation of nuclear factor-kappaB (NF-kappaB) into the nuclei. Interestingly, the ox-LDL-induced ICAM-1 expression and NF-kappaB relocation could be attenuated by addition of ginkgolide B. Moreover, ginkgolide B significantly reduces ox-LDL-induced generation of reactive oxygen species (ROS). In conclusion, ginkgolide B may decrease inflammatory responses induced by ox-LDL via blocking NF-kappaB signaling and inhibiting ROS generation in HUVECs.